Coli surface antigen 5 (CS5) (CS5)

Coli surface antigen 5 (CS5) is a critical colonization factor (CF) expressed by Enterotoxigenic Escherichia coli (ETEC), a major cause of acute watery diarrhea in children in developing countries and travelers [1.2.1, 1.2.2]. It is a fimbrial protein that forms rigid, thread-like appendages on the bacterial surface, facilitating the attachment of ETEC to the epithelial cells of the small intestine [1.2.4, 1.3.3]. This adherence is a prerequisite for the delivery of heat-labile (LT) and heat-stable (ST) enterotoxins that cause fluid secretion and diarrhea [1.1.1, 1.4.1]. The expression of CS5 is notably regulated by host environmental cues, such as the presence of bile salts like sodium glycocholate, which significantly up-regulates its production in the gut [1.2.1, 1.3.2]. Due to its high prevalence in clinical isolates and its essential role in pathogenesis, CS5 is a major target for ETEC vaccines, including the oral inactivated vaccine EtVax and the live-attenuated vaccine ACE527 [1.2.5]. These vaccines aim to elicit protective antibodies that block CS5-mediated colonization, thereby preventing the onset of disease [1.1.1, 1.2.5].

Other names

CS5Coli surface antigen 5CS5 fimbriaeCS5 adhesinCFA/IV component

Induction of mucosal and systemic antibodies that bind to the CS5 fimbriae, preventing bacterial adherence to the intestinal epithelium and subsequent colonization.